Researchers used underwater loudspeakers and played sounds associated with healthy reefs to lure in fish. Researchers say fish play a vital role in maintaining healthy coral reefs (Image credit: James Cook University)
A team of researchers from Australia’s James Cook University and the Australian Institute of Marine Science, alongside researchers from the UK’s University of Exeter and University of Bristol, recently used underwater loudspeakers in an attempt to entice fish back to dead coral reefs. And it worked.
The speakers played replicated sounds of healthy reefs using a process called “acoustic enrichment.” They placed the speakers on over 30 dead patches coral in the Great Barrier Reef over the course of 40 days. They found that twice as many fish came and stayed compared to the patches where no sound was played.
"Healthy coral reefs are remarkably noisy places -- the crackle of snapping shrimp and the whoops and grunts of fish combine to form a dazzling biological soundscape. Juvenile fish hone in on these sounds when they're looking for a place to settle," said one of the study's authors, Steve Simpson, a professor of marine biology and global change at the University of Exeter. Once reefs degrade, they become “ghostly quiet” as shrimps and dish disappear. But by replicating the sounds, it attracts fish to swim over once again.
So why do scientists want the fish to return? They could help the ecosystem recover and help give those dead coral reef patches a second chance. According to Tim Gordon, the lead author of the study and another marine biologist from the University of Exeter, fish play an important role in keeping coral reefs functioning. He says increasing the fish population in these areas could “help to kick-start natural recovery processes, counteracting the damage we're seeing on many coral reefs around the world.”
This could be a big breakthrough in helping the Great Barrier Reef recover. It has suffered multiple large scale “bleaching” events caused by above-average water temperatures in the last two decades, including back-to-back occurrences in 2016 and 2017. These rising temperatures not only damage the reef but comprises its ability to recover.
It sounds promising, but can this really work on such a large scale? And will they be able to keep the fish there on sound alone? Researchers are optimistic but know that there’s still a lot of work ahead to help the reef recover.
"Acoustic enrichment is a promising technique for management on a local basis," said Andy Radford, a co-author, and professor in behavioral ecology at the University of Bristol. "However, we still need to tackle a host of other threats including climate change, overfishing, and water pollution, in order to protect these fragile ecosystems," he said.
Radford also believes that more research needs to be done to monitor reefs longer period, in order to fully understand how the loudspeakers influenced the fish. Though this is just the beginning, it’s clearly a step in the right direction.
Imagine what the fish must be thinking when they arrive at the reef...
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